The MPS engineering team is working on an emergency ventilator inspired by the open-source MIT design to aid in the fight against COVID-19. The ventilator electric motor in this design mechanizes a BVM bridge ventilator to quickly automate what is normally a manual process. The ventilator motor controls are powered by a notebook power brick or a battery backup system through an MPS DC/DC boost board. The ventilator BLDC motor is equipped with an encoder, controller, and motor drivers. The ventilator BLDC motor control/ventilator motor driver use a motor driver module and angle position sensing to automate the squeezing of the standard BVM. This type of ventilator motor control can safely and easily automate a manual resuscitator when a full ICU ventilator may not be available.

Open source ventilators usually require fairly accurate position and speed control of the motor, in order to achieve the desired tidal volume and breath rate. A regular DC motor (either or brushless) or stepper motor cannot achieve these functions due to lack of close loop control. One option is to use a servo motor. A servo motor is a permanent magnet synchronous moor (PMSM) with built-in optical encoder. The servo motor is expensive, and often heavy and bulky. The MPS Smart Motor EVKT is a lower cost alternative to the traditional servo motor. It uses a regular BLDC motor with integrated MPS proprietary FOC control engine and magnetic position sensor, can lower the total cost by 50% and reduce the solution size by 30%.

MPS products used in this design:

• Motor Controller MMP742038-24-C
• Smart Motor MSM942038-24
• Other smart motor modules

Figure 1: MPS Open-Source Ventilator